Page 26
MUTCD 11th Edition
- Signal Phase—the right-of-way, yellow change, and red clearance intervals in a cycle that are assigned to an independent traffic movement or combination of movements.
- Signal Section—the assembly of a signal housing, signal lens, if any, and light source with necessary components to be used for displaying one signal indication.
- Signal Sequence (Sequence of Indications)—the order of appearance of signal indications during successive intervals of a signal cycle.
- Signal System—two or more traffic control signals operating in signal coordination.
- Signal Timing—the amount of time allocated for the display of a signal indication.
- Signal Visor—that part of a signal section that directs the signal indication specifically to approaching traffic and reduces the effect of direct external light entering the signal lens.
- Signing—individual signs or a group of signs, not necessarily on the same support(s), that supplement one another in conveying information to road users.
- Simultaneous Preemption—notification of approaching rail traffic is forwarded to the highway traffic signal controller unit or assembly and railroad or light rail transit active warning devices at the same time.
- Site Roadways Open to Public Travel—Roadways and bikeways on sites of shopping centers, office parks, airports, schools, universities, sports arenas, recreational parks, and other similar business, governmental, and/or recreation facilities that are publicly or privately owned but where the public is allowed to travel without full-time access restrictions. Two types of roadways are not included in this definition: (1) roadways where access is restricted at all times by gates and/or guards to residents, employees, or other specifically-authorized persons; and (2) private highway-rail grade crossings. Site roadways open to public travel do not include parking areas (see definition in this Section), including the driving aisles (see definition in this Section) within those parking areas.
- Special-Purpose Road—a low-volume, low-speed road that serves recreational areas or resource development activities.
- Speed—speed is defined based on the following classifications:
- Average Speed—the summation of the instantaneous or spot-measured speeds at a specific location of vehicles divided by the number of vehicles observed.
- Design Speed—a selected speed used to determine the various geometric design features of a roadway.
- 85th-Percentile Speed—the speed at or below which 85 percent of the motor vehicles travel.
- Operating Speed—a speed at which a typical vehicle or the overall traffic operates. Operating speed might be defined with speed values such as the average, pace, or 85th-percentile speeds.
- Pace—the 10 mph speed range representing the speeds of the largest percentage of vehicles in the traffic stream.
- Speed Limit—the maximum (or minimum) speed applicable to a section of highway as established by law or regulation.
- Speed Zone—a section of highway with a speed limit that is established by law or regulation, but which might be different from a legislatively-specified statutory speed limit.
- Splitter Island—a median island used to separate opposing directions of traffic entering and exiting a roundabout.
- Station Crossing—a pathway grade crossing that is associated with a station platform.
- Statutory Speed Limit—a speed limit established by legislative action (such as Federal or State law) that typically is applicable for a particular class of highways with specified design, functional, jurisdictional, and/or location characteristics and that is not necessarily displayed on Speed Limit signs.
- Steady (Steady Mode)—the continuous display of a signal indication for the duration of an interval, signal phase, or consecutive signal phases.
- Stop Line—a solid white pavement marking line extending across approach lanes to indicate the point at which a stop is intended or required to be made.
- Street—see Highway.
- Supplemental Signal Face—a signal face that is not a primary signal face but which is provided for a given approach or separate turning movement to enhance visibility or conspicuity.
- Swing Gate—a self-closing fence-type gate designated to swing open away from the track area and return to the closed position upon release.
- Symbol—the approved design of a pictorial or graphical representation of a specific traffic control message for signs, pavement markings, traffic control signals, or other traffic control devices, as shown in the MUTCD.
Sect. 1C.02
December 2023
